Spectroscopic studies on the complexation of some transition metals with Chloramphenicol drug

Complexes of Chloramphenicol (CHL, H2L) with Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) were obtained in methanolic solution at ∼pH 7.00–7.50 using NaOH. Elemental analyses are consistent with the formulas: Na2[M(CHL)2(H2O)2]·nH2O where (M = Mn(II), Co(II) and Ni(II), and n = 2, 4 and 6), Na2[M(CHL)2]·nH2O where (M = Zn(II), Cd(II) and Hg(II), and n = 0, 1, and 2), and [Cu(CHL)2]·4H2O. The IR spectra of the prepared complexes indicate that, the metal coordinated via both hydroxyl groups, while the Cu(II) complex is coordinated through one of the hydroxyl groups and carbonyl of the amide group. Except for Cu2+ all the metal ions form six membered ring complexes with Chloramphenicol. These complexes have been characterized by elemental analysis, magnetic susceptibility, molar conductance, infrared, electronic spectral and thermogravimetric (TGA/DTG) measurements. The CHL ligand as well as their complexes have been checked against some kinds of bacteria and fungi and give a significant effect. The kinetic thermodynamic parameters such as: E∗, ΔH∗, ΔS∗ and ΔG∗ are estimated using Coats and Redfern as well as Horowitz–Metzger equations.